This invention generally relates to an electrolytic cell of the type which includes a cell enclosure, a plurality of anodes, a foraminous cathode extending between adjacent anodes, and a diaphragm or membrane in the anode-cathode gap. More particularly, this invention relates to such electrolytic cells having an improved anode mounting structure for attaching anodes to an anode mounting plate so the anodes can be moved laterally with respect to the anode mounting plate to adjust the anode-cathode gap.
In a Hooker-type electrolytic cell, for example, the anodes are attached to an anode mounting plate which is usually the base of the cell. Foraminous iron or steel cathodes coated with a diaphragm are suspended from the sides of the cell body and extend between adjacent anodes.
In cases where the anodes are fabricated from graphite, the anodes are secured with lead and an asphaltic sealer in the cell base. Recently, the graphite anodes have been replaced by metallic anodes having a suitable conducting coating on the outer surface of the anode.
U.S. Pat. No. 3,591,483, issued July 6, 1971, to Loftfield, et al, describes one method of attaching metallic anodes to the cell base. According to this patent, the cell base is of conducting material, the interior of which is covered with an electrically non-conductive sheet. The anodes include an anode riser having a flange in the lower portion thereof and a portion extending from the flange through an aperture in the cell base. The anode posts are threaded and secured to the cell base with threaded nuts.
With the anodes mounted in the manner described above, they cannot be adjusted laterally with respect to the base plate to vary the anode-cathode gap. Substantial space is required between the anode and the cathode during assembly of the cell to prevent scraping between them due to misalignment or dimensional deficiencies. Such scraping is undesirable because it may result in the breaking of the diaphragm which would cause operational problems due to the mixing of the anode and cathodic products. In the case where the diaphragm is asbestos, scraping might also cause asbestos particles to break loose from the diaphragm, which is also undesirable. Therefore, the anode-cathode gap must be wide enough to permit assembly of the cell. However, it is desirable to keep the anode-cathode gap small since the resistance of the electrolyte in the gap to the passage of electrolyzing current raises significantly the operating voltage of the cells. Thus, the wider the gap, the greater the energy consumption and the more costly the cell is to operate. The space required to permit proper assembly of the components of the cell is usually greater than the optimum anode-cathode gap which results in the most efficient operation of the cell.
In order to overcome the above problem, it has been proposed previously in U.S. Pat. No. 3,796,648, issued Mar. 12, 1974, to Conner, Jr., et al, to attach the anode post to the base plate by having a threaded stud portion thereof protrude through an enlarged hole in the base plate. When the nuts are untightened, the anodes can be moved laterally with respect to the base plate either manually or by insertion of the cathodes between them with the use of spacing elements.
A similar approach is disclosed in U.S. Pat. No. 3,803,016, issued to Conner, Jr., on Apr. 9, 1974. According to the disclosure of this patent, each of the anodes includes adjustable anode sections provided with independent anode mounts for each section. The anode mounts extend through an enlarged aperture or slot in the base plate and are secured thereto by means of a threaded nut. When the nut is untightened, each anode section can be moved to vary the width of the anodes so that the space between adjacent anodes is enlarged to permit installation of the cathodes or minimized to narrow the distance between the anode and the diaphragm surface on the cathode.
It is to be noted that according to the arrangements discussed above, no mechanism is provided which will positively move the anodes. According to the described arrangements after the nut is loosened, the anodes must be either moved manually or by cathode as it is inserted between the anodes.
Accordingly, it is an object of this invention to provide an improved anode mounting structure for attaching anodes of an electrolytic cell to an anode mounting plate wherein the anodes can be adjusted to vary the anode-cathode gap.
It is a further object of this invention to provide an improved adjustable anode mounting structure for use in connection with electrolytic cells wherein the mounting structure can be used to positively move the anodes.
According to the broad aspects of the invention, attaching means are provided for attaching the mounting posts of an anode of an electrolytic cell to an anode mounting plate. The attaching means includes a portion extending through the anode mounting plate and adapted for rotation therein whereby upon rotation thereof lateral movement with respect to the base plate is imparted to the anode.
The attaching means preferably includes a crank having one end extending through the anode mounting plate and the other end mounted in the mounting post. Rotation of the end of the crank extending through the plate member will result in movement of the anode laterally of the plate member.